<template>
<div>
  <router-link tag="div" to="/" class="header-abs" v-show="showAbs">
    <div class="iconfont header-abs-back">返</div>
  </router-link>
  <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
    <router-link to="/">
      <div class="iconfont header-fixed-back">返</div>
    </router-link>
    景点详情
  </div>
</div>
</template>

<script>
export default {
  name: 'DetailHeader',
  data() {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll() {
      const top = document.documentElement.scrollTop
      console.log('滚动距离：'+top);
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = {
          opacity
        }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  /**
   * 全局解绑
   * @return {[type]} [description]
   */
  mounted(){
    window.addEventListener('scroll', this.handleScroll)
  },
  destroyed(){
    console.log('结束绑定');
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>

<style lang="stylus" scoped>
  	@import '~@/assets/styles/varibles.styl';

.header-abs{
  position: absolute
  left: .2rem
  top: .2rem
  width: .8rem
  height: .8rem
  line-height: .8rem
  border-radius: .4rem
  text-align: center
  background: rgba(0, 0, 0, .8)
}
  .header-abs-back{
    color: #fff
    font-size: .4rem
  }
      .header-fixed{
        z-index: 2
    position: fixed
    top: 0
    left: 0
    right: 0
    height: $headerHeight
    line-height: $headerHeight
    text-align: center
    color: #fff
    background: $bgColor
    font-size: .32rem
      }

    .header-fixed-back{
      position: absolute
      top: 0
      left: 0
      width: .64rem
      text-align: center
      font-size: .4rem
      color: #fff
    }


</style>
